1. Field of the Invention
The present invention relates in general to recording media, and relates in particular to an ink jet recording sheet having a long shelf life and excellent ink absorption and fixation properties, to provide clear high quality image suitable for use in ink jet printers.
2. Description of the Related Art
Increasing popularity of ink jet printers in recent years owes its success to the high quality of recorded images providing clarity, tonality and excellent color reproduction. Ink jet printers use inks which do not dry quickly to avoid plugging of the jet nozzles by dried ink particles. Because such inks are generally made by dissolving or dispersing such materials as binders, dyes, solvents and special purpose additives in water, recording sheets for use with ink jet printers are required to have an ability to absorb water. Therefore, receding sheets in use are provided with a quality to absorb water sufficiently and yet avoid the creation of unclear images.
To improve the receiving quality of water based ink into the recording sheet, i.e. ink absorption capability, there have been proposals to provide for an ink receiving layer in the recording sheet. The ink receiving layer is generally made by coating a base paper with an aqueous coating composed primarily of polyvinyl alcohol and containing materials having wetting affinity for the inks used in ink jet printers, such as lithiumchloride glycol, gelatin, hydroxyl ethylcellulose or carboxyl methylcellulose.
However, such conventional types of recording sheets, in practice, not only did not exhibit sufficient ink absorbing quality but presented an additional problem of inadequate drying (fixation) property. On the other hand, if an attempt is made to improve ink absorbability to a level sufficiently high to satisfy the fixation property, a problem of ink bleeding is created thus lowering the image clarity and degrading other recording qualities in general. It also causes associated problem of shelf-life such as bunching caused by the absorption of humidity and the resulting sticking of papers due to the formation of gooey surface.